Squid + Squidguard - redirect http traffic

Im having trouble figuring out which is the best way to redirect the traffic for a certain subnet. Basically i want to deny the access for a certain subnet to the internet. And i want it to always redirect the user to a specific (local) website. We have a squid3 + squidguard proxy here that is managing the blocking of certain websites. I thought i could do it with it by using a whitelist and block everything else. I tried to add this to the squidguard config dest whitelist { domainlist whitelist/domains urllist whitelist/urls } test{ pass whitelist none redirect http://bla.intern } and added the url http://bla.intern in the domains and urls file Now i can visit http://bla.intern but when visiting other websites its not redireccting me just denying access. Is there a better way to do this? Maybe over iptables?